The field of the present invention is that of connector apparatus or adapters for securing an electrical appliance to an electrical power distribution track such as the type that is utilized in track-lighting. More particularly, the present invention concerns connector apparatus having a novel and improved mechanism for grounding for use with a grounded track.
Electrical power distribution tracks to which light fixtures or electrical outlets may be connected at any given point by the use of adapters or connector apparatus, are well known to the field of interior lighting. Typically, the track contains a slot for housing insulating inserts which support electrical current-carrying conductors. The track is usually made of metal while the insulating inserts are made of an insulated plastic material such as polyethylene.
The connector apparatus consists of a body with a plug protruding therefrom for engagement with the slot of the track. Ridges or ledges are provided on the plug to engage corresponding ledges or ridges in the slot of the track for attachment of the connector apparatus to the track. Electrical contacts on the plug of the connector apparatus engage the current-carrying conductors in the slot of the track to provide electric power to lighting fixtures, electrical outlets or other electrical appliances attached to the connector apparatus. For safety reasons, a line separate from the current-carrying lines and conductors must be provided to ground these fixtures, outlets and appliances.
One type of grounding system well known in the prior art provides a grounding contact or tab in the plug of the conductor apparatus which engages a ground conductor insulated in the track slot. However, this type of grounding mechanism proves unsatisfactory because in addition to supporting a hot and neutral conductor bus bar, the slot of the track must also support a grounding conductor bus bar which adds to the complexity, weight and cost of the track.
Another type of grounding system developed to alleviate some of the above-mentioned problems provides the grounding conductor in the connector apparatus. For example, as shown in Republic of China Patent No. UM-32635 to R. S. Stringer, a grounding conductor in the connector apparatus includes a spring loaded metallic spike that is biased against a grounded metallic track to effect electrical contact therebetween thus eliminating the need for an additional conductor bus bar in the track.
However, although the spike grounding system may reduce the cost, weight and complexity of the track, it still has an overly complex connector apparatus which requires an excessive number of parts due to the placement of the grounding conductor therein.